1. Field of the Invention
This invention relates to a method and apparatus for filling, melting and discharging a filling material of low melting point to be used for bending a workpiece.
2. Description of Background Art
When it is required to bend a pipe having multiple pipes disposed within each other, a filling material of low melting point is supplied into the tubular workpiece to permit bending of the inner and outer pipes with accuracy. However, conventionally, the steps of filling the filling material of low melting point into a straight tubular workpiece, bending the straight tubular workpiece to form a bent tubular workpiece, and heating to melt and discharge the filling material after moving the bent tubular workpiece into a discharging furnace have been carried out at different locations.
Therefore, the filling material, when molten and discharged, is kept in a reservoir for maintaining the heat of the discharged liquid and then released from the reservoir for maintaining the heat to the next straight tubular workpiece by means of a pump.
Also, generally, the straight tubular workpiece is supported by a carrier which is provided with a nozzle adapted to engage the upper end portion of the straight tubular workpiece for supplying the filling material thereto, and a sealing member adapted to engage the lower end of the straight tubular workpiece.